1. Field of the Invention
This invention relates to an elevator system particularly adapted for use in small buildings such as private homes.
2. Description of the Prior Art
In recent years, persons of advanced age have been increasing at a rapid rate in Japan and other places in the world, and along with this ageing of society has come an increase in the number of people who desire an elevator system be installed in their two- or three-storied private homes. However, conventional elevator systems have been developed in accordance with demands for large-sized elevator systems in large office buildings, cooperative housing, or the like and if the large-sized conventional elevator systems suitable for these large buildings are miniaturized for use with small-sized buildings such as private homes, there will be many inconveniences particularly from the view points of installation space efficiency, production economy and maintenance costs, etc. Specifically, many elevator systems in general employ a well-bucket type lifting system in which an elevator car and a counterweight are connected to each other by a main or hoisting rope, but this type of lifting system requires a relatively greater installation space for the counterweight as compared with the elevator car, and hence is not suitable for small-sized elevator systems.
On the other hand, there has been known a drum-type elevator system which does not use any counterweight as described, for example, in Mitsubishi Denki Technical Information, volume 57, number 11, page 7(745), FIGS. 2 to 4, issued on Nov. 25, 1983. This drum-type elevator system is constructed such that an elevator car is caused to move vertically by winding and rewinding a hoisting rope around a drum without use of any counterweight. Thus, a drum-type elevator system employing no counterweight can be produced with a small size and suitable for installation in applications with limited available space.
Although in the above-described conventional elevator system, no counterweight is employed, a machine room for installation of an electric motor for driving a drum is required instead, and accordingly, it is essential to provide a machine room in a home installation which thereby take up valuable portion of the relatively small space available in most homes, making it difficult to effectively utilize available space.
Further, the above-described conventional elevator system of the winding drum type requires safety devices including an emergency stopping mechanism, a speed governor and the like which will be operated in case of a break of the main or hoisting rope. In a compact or small-sized elevator system, however, it is unfavorable to employ the winding drum and the safety devices as referred to above in terms of the installation space and the production costs involved.